Concrete compacting tool



March 25, 1941. J. F. BARRY ETAL' CONCRETE COMPACTING TOOL Filed July 8, 1939 a Q Q n QM a ,s s umw. 5M Q wx mm n G u a Il, w

' /NVENTORSIJJHARLEY Patented Mar. as, 1941 -T y 2,236,392.

UNITED STATES rATENT OFFICE 'CONCRETE com-ACTING 'roon Joseph F.' Barry, Brooklyn, N. Y., and Joseph J.

Harley, Tenaily, and Walter S. Hayford, Morristown, N. J., assixnors to Bell Telephone Laboratorles, Incorporated, New York, N. Y., a corporation of lNew York Application July s, 1939, serial Na'zsaasc 3 claims. (cl. 259-1) This invention relates to concrete compacting Fig. 2 is a cross-sectional view taken on line tools of the pneumatic type. 2-2 of Fig.- 1;

'I'he object of the invention is to simplify the Fig. 3 is a view of the elastic element partly construction of vsuch tools and improve their in section; -5 operation. Fig. 4 is a detailed view; and

In accordance with this invention a concrete Figs. 5A, 5B and 5C are views showing the compacting tool of the pneumatic type is procyclic expansion changes of the elastic element vided in which a hollow elastic member which is when acted upon by a constant air pressure durclosed at one of its ends is expanded successively ing the operation of the tool in the compacting longitudinally and circumferentially by a source of theconcrete mix. of constant air pressure distributed through air In the tool of the invention, a metallic manpaths formed by the elastic member in cooperadrel M is formed at one of its ends with a hemi- 'tion with a mandrel to which the open end of spheric portion II, a cylindrical portion I3 havthe elastic member is secured, the longitudinal ing at its periphery a circular ridge portion I2I r, 1i expansion of the elastic member followed by its adjacent the plane of the hemispheric portion, l" circumferential expansion and its retraction and a circular groove I4 in th Cylindrical portion. under the medium of its own resiliency being Over the mandrel'M thus formed is fitted anA eiected at a rate of vibration which is dependelastic element I6 such as rubber, having an inent upon the air pressure used, the stiffness of teriorly formed ridge I'I shown in Figs. l and 3 the elastic element, and the size of the`air paths. engaging the circular groove I4 in tlle mandrel 2O More specifically, a-hollow elastic member is M while va strip I8 of abrasion resisting material tightly iitted to a mandrel having a hemispheriis vulcanized in-the rubber in registry or coactcal end portion, a peripherally disposed ridge ing relation with the peripheral ridge I2. adjacent the plane of the hemispherical portion, 'I'he elastic element I6 is further held in posiand a cylindrically-shaped portion, the cylintion on-the mandrel M at its open end by the drical portion havingan annular recess formed engagement of a metallic sleeve I9 fitted over therein into which a similarly shaped portion the reduced end portion of this element while formed with the elastic element its for securing the other end of sleeve I9 is secured to collar. this end of the elastic element to the mandrel. I5 of mandrel M by a. number of screws 2|, 22

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'30 Means fitted over the elastic element opposite and 23, shown in Figs. 1 and 2. The otherl end 30 its closed end and secured to the periphery of of sleeve I9 is welded to a connector member the mandrel further secures the elastic member CM having a reduced end portion for receiving to the mandrel and provides means for connectone end of a. hose 28 to be secured thereon as ing air outlet paths in the mandrel to one end by wire clamps 29 and 30, this hose serving as of 9, hose forming an exhaust path for the coman exhaust path for the compressed air, as will 3U pressed air, while a tubing which is disposed be hereinafter described in detail, concentric to the air outlet hose is connected to The mandrel M is provided with a central an air inlet path in the center of the mandrel longitudinal air inlet path 24 which is screwand longitudinally thereto, this inlet path being threaded as at 25 for receiving a similarly screwnormally closed by the tension of the elastic el@ threaded end of a tubing 26 having its other 40 ment on the hemispherical portion of the manend connected to a hose 21 disposed concentric drel, and means vulcanized in the expansible to the hose 2B, while. the other end of hose 2I element at its pointv of contact with the ridge is provided with a valve 3l for connection with carried by the mandrel is provided for preventan ordinary air compressor (not shown).

ing excessive wear to the elastic element at this The mandrel M is provided 4with series of 45 point upon the continued successive elongation radially disposed holes such as HI-HI shown and circumferential expansion of the elastic elein FigS- 1. 2. 5A. 5B and 5C and the holes HI-HI ment for compacting the concrete into which the lof each series communicate in respective longitool is applied. tudinally disposed holes as HIY, forming air ex- Other novel features and advantages of the, haust paths leading toward the central air out- '50 invention will appear by the following descriplet path CO and hence into the annular or contion and by the claims appended thereto, refcentric space formed by the hose 28 and the air erence being had to the accompany drawing in inlet hose 21, which: In the operation of the tool of vthe invention,

Fig. l is anv assembly view partly in section; with the elastic member I6 in position on the 55 mandrel M as shown in Figs. 1 and 5A and with the air inlet tube 21 connected to a source of compressed air through the operation of valve 3l, the air entering into the central air path formed by hose 21, the tubing 26 and the bore 2l in the mandrel M causes the momentary elongation of the elastic member I 6 and thereby relative movement between the mandreLM and said elastic member. Upon the movement of mandrel M relative to the elastic member Il from the positionshown in Fig. 5A to the position shown in Fig. 5B which is now under its retractlle effect, the member I6 is caused to expand circumferentially from its point of contact with the ridge I2 to a. point shown in Fig. 5C while simultaneously coming in contact with the end of the mandrel for..closing this air inlet path. Under this condition the compressed air is permitted to escape through the path formed between the peripheral ridge I2 and the ring I8 of abrasive material and hence into the series `of radiall holes HI-HI and corresponding exhaust holes HIY leading to hose 28 concentric to tubing 21. The passing of the compressed air between the ridge I2 and the ring I8 of abrasive resisting material and the simultaneous return of the mandrel in contact with the end ofthe elastic member I6 successively translates the constant air pressure intovpulsing air current and this cycle of operations is continued as long as the tool is connected to the compressed air which may be interrupted by the closing of the valve connecting the inlet air paths to the air compressor.

What is claimed is:

1. A pneumatic concrete compacting tool comprising a mandrel having an air inlet path longitudinally thereof, an elastic member fitted under tension over said mandrel to normally close said air inlet path at one end of said mandrel, means carried by said mandrel at its periphery cooperating with said elastic member to form a A circumferential air outlet path, the elastic mehr ber under air pressure from said air inlet path being caused to alternately expand longitudinally and circumferentially upon the successive passing of the air under pressure from said air inlet path to said outlet air path.

2. A pneumatic concrete compacting tool comprising a mandrel having a longitudinally disposed air inletpath and al ridge at its periphery, an elastic member fitted over said mandrel and having one of its ends secured thereto and its other end normally closing said air inlet path, a plurality of exhaust vpaths in said mandrel contiguous to said ridge, a connector member secured to said mandrel contiguous to said exhaust path and a connector member'secured to said mandrel contiguous to said air inlet path, disposed concentric to the mst-mentioned connector, the compressed air from said inlet path causing the expansion of said elastic member for successively opening said air inlet path at the end of said mandrel and the outlet path formed by said ridge and said elastic member.

3. A pneumatic concrete compacting tool comprising a mandrel formed with a hemispheric portion and a ridge portion, a cylindrical portion and a collar portion in the cylindrical portion,

an elastic member concentrically disposed on said mandrel and having one of its ends secured to said collar, said mandrel having a centrally 1ongi'tudinally disposed air path, a tubing connecting said air path to a source-oi compressed air, the compressed air successively expanding said elastic member at its points of contact with the end of said mandrel and said ridge, an. air exhaust path formed in the cylindrical portion of said mandrel and a tubing connecting said air exhaust path disposed concentric to the rst-'menticned tubing.

JOSEPH F. BARRY.

JOSEPH J. HARLEY. WAL'IER. S. HAYFORD. 

